1. Field of the Invention
The present invention relates to an electronic endoscope apparatus for reducing radiation of undesirable noise from an electronic endoscope.
2. Description of the Related Art
Generally, an electronic endoscope is arranged as follows. That is, a solid-state image pickup element is arranged at a forward end of the electronic endoscope. An image pickup cable extends through a circuit substrate and electronic portions which are connected to the solid-state image pickup element. The image pickup cable is adapted to be inserted into and to pass through the interior of an insertion portion, an operation portion and a universal cord of the endoscope, and is connected to a connector portion which is provided at an end of the universal cord.
Further, the electronic endoscope is connected to a processor, a light source device, a monitor and possibly other accessory equipment and is used as an electronic endoscope apparatus. A plurality of operation switches, which are arranged at the operation portion of the electronic endoscope apparatus, make it possible to provide a stationary image, changeover of light modulation and control of external pieces of equipment. Within a universal cord, switch cables which extend from the operation switches are inserted and pass therethrough and are connected to the connector portion.
On one hand, in recent years, also with respect to electrical equipment devices which are used within a hospital, it has become more desirable to conduct electromagnetic compatibility ("EMC") countermeasures. For this reason, with respect to the above-described electronic endoscope apparatus, EMC has been mentioned as a technologically important matter.
Accordingly, in order to prevent an electrical signal which is used in the electronic endoscope apparatus from being radiated external of the apparatus to cause malfunction of other pieces of electronic equipment, or to prevent noises which are radiated from other pieces of electronic equipment from mixing and interfering within the electronic endoscope apparatus to reduce the image quality of an endoscope image, thus causing malfunction of a control signal, the connector portion which is provided with many electrical contacts particularly requires increased shielding and protection from radiated noise.
For this reason, an arrangement in which a mechanism is provided which shields the connector portion with a metal member, and an arrangement whose construction is such that an electromagnetic absorber member is provided between the electronic endoscope and a patient circuit are disclosed in Japanese Patent Unexamined Publication No. HEI 4-183432 (183432/1992). Moreover, disclosed in Japanese Patent Unexamined Publication No. HEI 6-142039 (142039/1994) is an arrangement in which a metal blade is provided within the universal cord, which has one end thereof conducted to a connector receipt, to thereby form electromagnetic screening or shielding means or electromagnetic interference countermeasure means.
However, there is the following problem. That is, for the construction in which the metal member is used to shield the connection portion, as described above, or for the construction in which the electromagnetic absorber member is provided between the endoscope and the patient circuit, as disclosed in Japanese Patent Unexamined Publication No. HEI 4-183432, or the like, the connector portion is large and bulky and is excessively heavy, thereby reducing convenience and ease of use.
Furthermore, in order to incorporate the electromagnetic interference countermeasure means into the universal cord, not only are many man-hours and many steps required, but also convenience in use is deteriorated. If the electromagnetic interference countermeasure means is once incorporated into the electronic endoscope, an electronic endoscope in which the electromagnetic interference countermeasure has been halted exists regardless of whether or not the EMC countermeasures are necessary. For this reason, even also in a case where there is no interference if the conventional or prior art electronic endoscope is used, an electronic endoscope which has been halted in the electromagnetic interference countermeasure must be used, and a user is not given a chance of selection. For this reason, it is desirable that the EMC countermeasures can simply be conducted or performed to the existing electronic endoscope, as the occasion demands, when the existing electronic endoscope is used in combination with, for example, an equipment which is likely to generate the undesirable noise.